Prevention of corrosion



Patented Sept. 2c, 1932 UNITED STATES.

PATENT, OFFICE BRADI'OBD S.'COVELL, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE MCKAY COMPANY, CF PITTSBURGH, PENNSYLVANIA, A COBPORA- v TION OF PENNSYLVANIA =80 Drawing.

This invention relates to a preparation for .preventmg corrosion and rust formation in the cooling systems of internal combustion engines.

'In cooling systems such as automobileradiators, for example, there is considerable corrosion even when water alone is used, and this corrosive action is even more pronounced when using certain of the anti-freeze solutions which are often employed during cold weather. It is not uncommon for corrosion to take place to the extent that the radiator tubes become more or less plugged with rust or heavily coated, thereby reducing considerablythe efilciency of the cooling system and v in some cases necessitating repairs or replacements therein. 1

' The preparation described in this inyention provides a means of keeping the cooling system of a new automobile practically free from corrosion throughout the life of the automobile. Tn the case of a used car, the cooling system maybe cleaned, and by using my preparation kept substantially corrosion-free thereafter.

My invention involves the use of small quantities of properly treated sulfonated fat-- ty acids in the liquid of cooling systems. The

treatment, described in detail in the following specification, involves the use of alkaline" or basic elements or radicals for the purpose of neutralizing'certain of the acids present in the sulfonated fatty acids.

The term sulfonated fatty acids, as re-' p 1 ferred to in this specification and in the aptir'e'd'alcohol-or diacetone alcohol and compounds-of alcohols; also certain polyhydric rnnvnnrron or CORROSION Application filed December 4, 1931. Serial No. 579,116.

alcohols such for example, as glycerine, and

ethylene glycol.

I prefer to use a sulfonated castor oil (also known as Turkey red oil) which has been such a point that the sulfuric acid content of the sulfonated oil is neutralized and the compound rendered water-soluble. However, I

neutralized by alkali. The addition of alkali should therefore be stopped at a oint at which the compound is water-solu 1e and free from sulfuric acid, but yet contains substagtial proportions of unneutralized fatty aci It is probably impossible to'lay down a general rule whereby the quantity of alkali prefer to leave the major part of the fatty acids of the compound in an acid state, un

needed can be predetermined. Sulfonated castor oil not yet clarified may contain vary- I ing quantities of residual sulfuricacid, not removed by the usual washing treatment...

The neutralization of the variable quantity ofsulfuric acid will in general involve partial neutralization of the sulfonated fatty acid content; it is desirable to carry the neutralization no further than is needed to neutra'l'ize the sulfuric acid-and renderthe compound water-soluble. These desired conditions may be ascertained for any given batch of material by usual chemical and physical tests. The proportion of free sulfonated fatty acid present. in the partially neutralized product will of course varyto someextent withthe'amount of alkali required to free the sulfonated oil from sulfuric acid. The percentage of fatty acid remaining unnei traliz'ed after this treatment should be from 60 to 90 per cent; I have found that the best results are obtained when from 7 0 to 80. per cent of the sulfonated fatty acids are left unneutralized. A dominant characteristic of my invention is therefore the provision in the cooling system of a corrosion-preventing agent containing an effective percentage of unneutralized sulfonated fatty acid.

The product is a transparent, amber-colored, oily liquid which maintains its clarlty even when mixed with upwards of of water; mixtureswith large quantities of water, however, have a somewhat milky or opalescent appearance. My product should be distinguished from a completely neutralized sulfonated fatty acid, since the latterwould be apt to cause foaming, blowing off of the cooling liquid in an automobile radiator, and the formation of bubbles preventing eificient cooling action. sulfonated castor oil treated in accordance with this invention is not appreciably affected by the mineral salts ordinarily present in water, and has no injurious effect on the copper tubing of the radiators or on the other metals in the cooling system, and is also harmless to the rubber connecting hose or any other parts of the system with which the liquid comes in contact.

In carrying out my invention in connection with automobile cooling systems, I prefer to add tothe cooling liquid approxnnately onetenth of one per cent by weight of sufonated castor oil which has been treated as" described with potassium or sodim hydroxide. Ordinarily, this partially neutralized product is added in the form of a 75% (or thereabouts) mixture of the oil in about 25% of water,the water being introduced during the various prior steps of preparation, including the ad- 1. vention may be employed diluted, more or less 3 dition of the alkali hydroxide which is done ordinarily in a water solution, although dry .viously as far as'eifectiveness in the'cooling alkali hydroxide may be used if desired. Ob-

system is concerned,'the' material of this inthan this quantity,.to any extent desired as long as the final solution in the system cone tains the requisite-percentage of the non-corrosive oil. This percentage, while preferably around one-tenth of one per cent asalready mentioned, may vary within fairly large limits as, far as anti-corrosive eifect is concerned. However, in order-for a cooling 'sys- .tem to work satisfactorily without overheat-,

ing', the percentage of the oil of this invention should not exceed three or four per cent, nor

should it, for the proper anti-corrosive re sults be less than fivef'one-hundredths' (.05)

of one per cent by weight'. This preferred product is not volatile, and therefore it does not need to be replenished. When the liquid in a cooling system becomes low, it is only sive, and making it unnecessary to add the two solutions separately, to the cooling systems. r

In making up anti-corrosive anti-freeze solutions in this way, it is obvious that a sufiicient amount of the anti-corrosive material should be used to give proper protection to the cool-' ing system.

- In place of a sulfonated castor oil neutralized as described, it is possible to use other sulfonated fatty acids (such as sulfonated sperm, olive, rapeseed, neatsfoot, or cocoanut oils), partially neutralized inthe same manner. However, since these other oils tend to form insoluble calcium and like soaps in hard water (causing an undesirable precipitate), their use is confined primarily to systems which employ soft water.

The product of the invention is suitable for use during the entire year. In summer it may be used with water alone in the cooling system; in winter it may be used with an antifreeze in the system.

' It should be understood that the present disclosure is for the purpose of illustration only andthat this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. Ananti-corrosive liquid for coolin systems containing a sulfonated fatty acifpartially neutralized to a point such that it. is water-soluble and contains no free sulfuric acid, characterized by the presence therein of a substantial quantity of unneutralized solu-' ble sulfonated fatty acid. 7 x

2. An anti-corrosive liquid for cooling sys tems containing sulfonated castor oil par-- tially neutralized to a point such that it is water-soluble and contains no free sulfuric .acid, characterized by the presence therein of a substantial quantity of unneutralized soluble sulfonated fatty acid.

3. An anti-corrosive liquid for cooling systems containing sulfonated castor oil partially neutralized and having from to 90 per cent of its sulfonated fatty acid ingredient existing as free unneutralized sulfo-' nated fatty acid.

4. An anticorrosive liquid for cooling systems containing sulfonated castor oil partially neutralized and having from to 80.

vper cent of its sulfonated fatty acid ingredient existing as free unneutralized sulfonated fatty acid. 5,- An anti-corrosivesolution for coolin systems including as ingredients sulfonated castor oil and an alkali adapted to neutralize emme sulfuric acid in the solution, characterized in that the major part of the fatty acid con-= stituent of the oil exists as unneutralized sulfonated fattv acid.v

6. Art of preventing corrosion in cooling systems which comprises. maintaining in the system a substantial concentration of a sul fonated fatty acid partly neutralized to ren== der it water-soluble and to prevent the presence of free sulfuric acid, but incompletely P neutralized so as to provide in thesolution a substantial quantity of free soluble sulfonated fatty acid.

7. Art of preventing corrosion in cooling systems which comprises maintaining in the system a substantial concentration of sulfonated castor oil partly neutralized to render it water-soluble and to preventthe presence of free sulfuric acid, but incompletely neutralized so as to provide in the solution a sub stantial quantity of free soluble sulfonated fatty acid.

Signed byme at Boston,Massachusetts, this 3d day of December. 1931.

BRADFORD S. COVELL; 

